This invention relates generally to an improved lock assembly for secure and releasible locking of a door or window or the like, particularly such as releasible locking of a semi-active door in a double door entry set. More specifically, this invention relates to an improved lock assembly having a slide bolt adapted for quick and easy fingertip actuation for displacement between an advanced locked position and a retracted unlocked position.
A typical double door entry set includes a primary door intended for routine opening and closing movement in the course of normal ingress and egress, in combination with a secondary or so-called semi-active door which is normally retained in a closed and locked condition. The primary door is normally equipped with door hardware including door handles or other suitable actuator devices for operating retractable door latch and deadbolt devices which commonly engage appropriate keepers mounted on the adjacent free side edge of the semi-active door. In turn, the semi-active door is normally equipped with locking hardware mounted at or near the free side edge thereof, generally proximate the upper and lower ends of the semi-active door, including retractable slide bolts for engaging appropriate keepers mounted respectively at the door header and sill. The slide bolts are normally advanced to a locked position engaging their respective keepers to retain the semi-active door normally in a closed and locked condition. However, when and if desired, these slide bolts can be retracted for disengagement from their respective keepers to unlock the semi-active door and permit opening thereof. In a common design, the slide bolts are exposed along the free side edge of the semi-active door for manual sliding displacement from the advanced locked position to the retracted unlocked position only when the primary door is open.
In the past, header/sill locking devices for a semi-active door of a double door entry set have generally comprised a simple slide bolt mounted in a track for sliding movement between the advanced and retracted positions, with frictional resistance between the slide bolt and track serving to retain the slide bolt in the selected advanced or retracted position. With this design, however, substantial frictional resistance sufficient to securely retain the slide bolt in the selected position of adjustment can result in a device that is difficult to operate manually. Reduced frictional resistance facilitates manual displacement of the slide bolt, but may result in reduced locking security by permitting undesired movement of the slide bolt to the retracted unlocked position in response to vibratory forces applied to the door. Such vibratory forces can be attributable to strong gusty winds, repeated shock forces from closure of the primary door, and/or an unauthorized intruder.
Improved security lock devices for header/sill locking of a semi-active door have been developed with a view toward overcoming these problems and disadvantages. See, for example, U.S. Pat. No. 5,290,077 which discloses and describes a header/sill lock assembly having elongated header and sill lock pins driven in unison between advanced locking positions and retracted unlocking positions in response to rotation of a thumbturn mounted near the free side edge of the semi-active door at an inner or indoor side thereof. While this header/sill locking arrangement beneficially provides significantly enhanced security locking of the semi-active door, the mechanism extends the entire height of the door and includes a significant number of parts to result in a device that is relatively complex and costly.
There exists a need for further improvements in and to security lock devices of the type designed for header/sill locking of a semi-active door or the like, particularly with respect to providing a relatively compact and mechanically simple device suited for quick and easy installation, and for correspondingly simple yet reliable operation while providing high security releasible locking of the door. The present invention fulfills these needs and provides further related advantages.
In accordance with the invention, an improved slide bolt unit is provided for releasibly locking a door or window or the like, such as a semi-active door in a double door entry set. The slide bolt unit comprises a compact and relatively simple lock assembly constructed from a relative minimum number of parts to include an elongated slide bolt adapted for quick and easy fingertip actuation for displacement with relatively low friction between an advanced position engaging a keeper on an adjacent header or sill or the like to lock the door in a closed position, and a retracted position to permit door opening. In the advanced and retracted positions, the slide bolt unit includes means for releasibly retaining the slide bolt in place.
In the preferred form, the slide bolt is carried by a channel-shaped housing adapted for recessed mounting into a side edge of a door or the like. A laterally turned actuator tab on the slide bolt is exposed through a position control slot formed in the housing for fingertip access at the door side edge. The actuator tab has a slotted profile defining lock shoulders biased by a spring for normally locking with the housing by seating within one of a pair of relatively wide pockets formed respectively at the opposite ends of the position control slot, corresponding respectively with the advanced and retracted positions of the slide bolt. The actuator tab further defines a narrowed central track having a width less than the lock shoulders thereon for alignment with a narrowed central segment of the position control slot upon fingertip depression of the actuator tab against the spring to permit quick and easy sliding displacement of the actuator tab along the position control slot from one end to the other. In the preferred form, the spring is formed integrally with a first end cap mounted at one end of the channel-shaped housing. A second end cap mounted at an opposite end of the housing defines a slide port for relatively low friction sliding displacement of the slide bolt between the advanced and retracted positions.